Hey guys I'd like to run a few things by you guys. I will be switching 120V 3A AC lines and am considering the following solution. I do not need synchronous switching by the way. This TRIAC http://www.digikey.com/product-detail/en/BT134-600E,127/568-5015-5-ND/1155119 The datasheet says its rated up to 4A and has a max gate current of 2A. This Optoisolator http://www.digikey.com/product-detail/en/MOC3021/160-1374-5-ND/385844 The datasheet lists the trigger current at about 15mA so I'll go with 20mA to be safe, and has a peak surge current of 1A. I will be triggering the optoisolator with 3.3V signals. So with these parameters I've gone with (3.3V - 1.3V) / .02A = 100 Ohms for the diode current limiting resistor on the optoisolator input. 170Vpk / .95A ~= 180 Ohms for the gate current limiting resistor on the triac I will be using this schematic http://www.simpleio.com/design/triacout/images/TriacOut4Sch_L.gif [Broken] Does this all sound good?